diff --git a/src/src/Plugins/Vue/vue_widget.cpp b/src/src/Plugins/Vue/vue_widget.cpp
--- a/src/src/Plugins/Vue/vue_widget.cpp
+++ b/src/src/Plugins/Vue/vue_widget.cpp
@@ -263,6 +263,42 @@
   .cursor= {224, 0, 0, 255},
   .radius= 12
 };
+
+// Tessera browser theme, added for the embedding application in 2026.
+// These colours apply to the native widgets and the page surround.
+#ifdef __EMSCRIPTEN__
+static const vue_theme vue_theme_tessera= {
+  .shade= { {205, 217, 206, 255}, {220, 226, 216, 255},
+            {241, 245, 235, 255}, {253, 253, 248, 255} },
+  .background= {246, 245, 239, 255},
+  .highlight= {228, 239, 223, 255},
+  .text= {23, 41, 35, 255},
+  .text_grey= {93, 107, 100, 255},
+  .border= {205, 217, 206, 255},
+  .field= {253, 253, 248, 255},
+  .field_focused= {241, 245, 235, 255},
+  .selection= {24, 68, 57, 255},
+  .selection_text= {253, 253, 248, 255},
+  .selection_soft= {217, 234, 219, 255},
+  .button= {253, 253, 248, 255},
+  .button_hover= {228, 239, 223, 255},
+  .button_down= {207, 228, 213, 255},
+  .pressed= {217, 234, 219, 255},
+  .scrollbar= {91, 116, 105, 120},
+  .scrollbar_hover= {56, 123, 100, 190},
+  .bar_line= {220, 226, 216, 255},
+  .bar_mode= {241, 245, 235, 255},
+  .bar_focus= {253, 253, 248, 255},
+  .tab_inactive= {235, 240, 229, 255},
+  .canvas= {235, 239, 230, 255},
+  .balloon= {253, 253, 248, 255},
+  .balloon_border= {205, 217, 206, 255},
+  .pre_edit= {241, 245, 235, 255},
+  .pre_edit_line= {56, 123, 100, 255},
+  .cursor= {24, 68, 57, 255},
+  .radius= 8
+};
+#endif
 
 static const vue_theme vue_theme_dark= {
   .shade= { {36, 36, 38, 255}, {52, 52, 55, 255},
@@ -474,6 +510,11 @@
 // the class tm-dark of the page: the dark colours of its frame (the tabs,
 // the menu of TeXmacs Vue, its dialogs); tm-theme-set tells the frame that
 // TeXmacs chose (before, the frame follows the system)
+EM_JS (int, vue_web_tessera_theme, (), {
+  return typeof document !== 'undefined' &&
+         document.documentElement.classList.contains ('tessera-embedded') ? 1 : 0;
+});
+
 EM_JS (void, vue_web_frame_theme, (int dark), {
   if (typeof document === 'undefined') return; // the node build: no page
   var c = document.documentElement.classList;
@@ -495,6 +536,12 @@
   else if (name == "light") dark= false;
   else dark= (SDL_GetSystemTheme () == SDL_SYSTEM_THEME_DARK);
   the_theme= dark ? vue_theme_dark : vue_theme_light;
+#ifdef __EMSCRIPTEN__
+  if (N(forced) == 0 && vue_web_tessera_theme ()) {
+    dark= false;
+    the_theme= vue_theme_tessera;
+  }
+#endif
   // TEXMACS_VUE_RADIUS overrides the rounding of the corners (0: square)
   string radius= get_env ("TEXMACS_VUE_RADIUS");
   if (N(radius) > 0 && is_double (radius))